File Size Limitations for Trimble Connect on HoloLens

First off, I love Trimble Connect and the possibilities it will bring moving forward. I am running Trimble Connect on my HoloLens and am in need of some assistance with a few issues I am having... Will there be some how-to guides coming out in the future on optimizing Revit models or Sketchup models to be viewed through the Lens? I have loaded a variety of models to my account and they look and work great from the online browser. When I view on the Lens I feel like anything over 100 MB just simply wont work or is verrrrry laggy/buggy. The smaller models work and operate fine and I feel like there's really not much of a difference between them and the larger ones besides size. If there were a guide with recommended settings, size limits, etc that would be very helpful. I am having my Revit coordinator playing the guess and check game as she continues to try and reduce the size on these and it is getting frustrating for both of us.

Great question! I feel your frustration. Model size and optimization is simultaneously the most important problem and the biggest area of opportunity for us on mixed reality today. In fact, we have a whole team of developers working on increasing these capabilities in our apps.

We plan to have some better walkthrough guides/videos out for the app in the coming weeks, which will be posted on this community and YouTube. Stay tuned.

It is, however, difficult to write in stone "what works" and "what doesn't", as it's not as simple as saying "anything less than 100mb will work". The size limitations are more directly tied to polygon/edge counts and densities. For example, you may notice that large models work much better in 1:1 scale than tabletop. This is because the HoloLens is only rendering where you're looking at any given time, so at 1:1 scale you're only rendering a slice of the pie versus the entire model at once. The team at SketchUp recommends tabletop models to stay under 200,000 edges, though you may be able to get away with more in immersive, as you're only taking a "slice of the pie" at a time.

The same numbers hold for Trimble Connect for HoloLens, too, though the app may be able to handle slightly larger models since SketchUp Viewer is rendering a lot more aesthetics like imagery and textures. Our team is actively working on new ways to load and render models and more properly deal with memory management, so we expect to continue to increase the model size capabilities as the year progresses.

With all of this said, here are a few best practices / thoughts to keep in mind:

HoloLens is an untethered device, so we have to temper our expectations as to what it can do. Obviously, TC web and desktop are going to be able to render larger models, as they have the processing power of your computer behind them. As we advanced on our software performance, as will the hardware industry continue to push what their next gen devices can do. We're at the very beginning of this tech!

Oftentimes when we're using HoloLens we tend to open way more data than we actually need for the use case we're exploring. It will obviously help the device to cut the data area down to whatever it is you're precisely looking at. This is cumbersome, I know, so we're working on adding a few tools to the app that will make this better (layer control, section planes, etc.)

Try to scale back specific objects that might be having a more concentrated impact on performance. As an example, I was once visualizing an airport model and it was working great. The next day I came back and it wasn't working anymore. After some digging, I realized that a colleague had pulled a little airplane into the model for aesthetics, not realizing that it was over 1m polygons just by itself. I've seen this with pipe fittings, mesh on desk chairs, high detail on rebar/anchor bolts, etc. Sometimes it's the little (usually curved) things that impact performance the most.

Hopefully, that gives a bit of help in the interim while we work to build out our documentation further. If you have more questions, feel free to reach out to me at mrp@trimble.com